If DC motor is supplied with AC current

Replies

• 

  zaveri

  D.C machines when supplied with a.c power may simply not work. i don't really know whether this may damage the field or armature coils.
  
  well i guess this question is similar to the most popular question asked in the mechanical section "what happens when petrol is used in diesel engines and vice versa?"
• 

  lal

  1. An AC supply periodically changes it's polarity along with the current direction. Assume the dc motor is a seprately excited one. Then the armature current will be periodically changing its direction and the magnetic flux will be constant. So what will probably happen in that case? Fleming has got a rule made for that.
  
  2. And similarly what will be the total impedance if an inductor is supplied by a dc current? Keep in mind dc doesn't change direction at anypoint and transformer basically is an inductor.
• 

  zaveri

  lal

  1. An AC supply periodically changes it's polarity along with the current direction. Assume the dc motor is a seprately excited one. Then the armature current will be periodically changing its direction and the magnetic flux will be constant. So what will probably happen in that case? Fleming has got a rule made for that.
  
  2. And similarly what will be the total impedance if an inductor is supplied by a dc current? Keep in mind dc doesn't change direction at anypoint and transformer basically is an inductor.

  
  In that case the d.C motor just won't start, will it ?
• 

  subhankar ghosh

  If dc is supplied to transformer,it will burn or damage the windings....bcoz as we know transformer has high inductance and low resistance...hence while input is dc,inductance is zero.and only low resistance left...hence the high current goes through windings ...which destroy the windings or device ...
• 

  Abhishek Rawal

  sree_23

  If a transformer is given DC what will happen?

  When DC is applied, the flux produced in core is constant & not alternating.
  
  Due to this there will be no flux linkage in secondary core. Hence, induced emf E = 0 in secondary winding.
  
  Due to this, the transformer core saturation will take place. Thus, primary side will draw excessive large current & at certain stage the coil will burn.
• 

  Jeffrey Arulraj

  The Fan(AC supply one used in houses) will not run and the Transformer will go in flames
  
  These devices uses the varations in frequency to work the way they are working now If you want to play with their working power do it with all safety precautions and never in large scale
• 

  zaveri

  Conqueror

  Fan will not run and the Transformer will go in flames
  
  These devices uses the varations in frequency to work the way they are working now If you want to play with their working power do it with all safety precautions and never in large scale

  
  what fan are you talking about ?
• 

  Jeffrey Arulraj

  zaveri

  what fan are you talking about ?

  The commercial Ceiling fan we use in our houses that which runs in Mains supply buddy
  
  PS: I will edit my previous post and make sure it is not a DC fan
• 

  lal

  zaveri

  In that case the d.C motor just won't start, will it ?

  Alternating current changes its direction of flow in every half cycle. So if the torque developed is clockwise in first half cycle, it will be reversed in the next one. A motor with a low moment of inertia will vibrate. Being heavy, but a large machine cannot vibrate at that frequency, I believe.
• 

  arunchary

  Motors are made to have stator and rotor concepts where it rotates according to Flemming and thumb rule.but coming to transformers are the two inductors where primary induces the flux to other(secondary)due to this transform of energy takes place.in Dc motor are use to made other things are discussed in this following video,